We propose to examine the effects of hyperglycemia on membrane proteins and membrane function of endothelial cells, red blood cells, platelets and macrophages in human and experimental diabetes mellitus. We want to examine the possibility that a variety of membrane proteins can undergo the type of nonenzymatic glycosylation that is exhibited by hemoglobin and is exaggerated by the diabetic state. Nonenzymatic glycosylation is the only known direct covalent modification of proteins which reflects hyperglycemia. While the rates of HGB Alc formation are about 1/4 percent per day in the presence of hyperglycemia, direct glycosylation rates of membrane proteins have not been studied in normal or diabetic subjects. We propose to search for such changes in SDS-PAGE purified, membrane protein using microdetermination technique for protein linked glucose which depends on sodium borotritide reduction of hydrolyzed sugars. The sensitivity of this technique is further heightened by the fact that, with the exception of collagen, glucose is not encountered as a normal component of mammalian glycoproteins. We also plan to evaluate functional parameters in each of the selected cells for concomittant changes which would reflect exposure to hyperglycemia. These functional parameters include micropinocytosis rates in endothelial cells, membrane stability and deformability in red blood cells, platelet aggregation and rates of phagocytosis in cultured macrophages. The proposed study provides independent asessments of membrane protein glycosylation and membrane function in cells which are exposed in the diabetic microcirculation in order to further assess the possible pathophysiological consequences of chronic hyperglycemia. The diabetic dog will be the source of endothelial cells, red blood cells and platelets. We will also study platelets and red blood cells in normal and diabetic humans. Cultured tumor macrophage cell lines provide stable and practical sources of phagocytic cells which can be studied in controlled glucose environments.